From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx128.postini.com [74.125.245.128]) by kanga.kvack.org (Postfix) with SMTP id 9681B6B0031 for ; Thu, 18 Jul 2013 08:48:08 -0400 (EDT) Message-ID: <51E7E400.4070705@oracle.com> Date: Thu, 18 Jul 2013 20:48:00 +0800 From: Bob Liu MIME-Version: 1.0 Subject: Re: [PATCH] mm: zbud: fix condition check on allocation size References: <1374071410-9337-1-git-send-email-heesub.shin@samsung.com> In-Reply-To: <1374071410-9337-1-git-send-email-heesub.shin@samsung.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Heesub Shin Cc: Andrew Morton , Seth Jennings , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dongjun Shin , Sunae Seo , Heesub Shin On 07/17/2013 10:30 PM, Heesub Shin wrote: > zbud_alloc() incorrectly verifies the size of allocation limit. It > should deny the allocation request greater than (PAGE_SIZE - > ZHDR_SIZE_ALIGNED - CHUNK_SIZE), not (PAGE_SIZE - ZHDR_SIZE_ALIGNED) > which has no remaining spaces for its buddy. There is no point in > spending the entire zbud page storing only a single page, since we don't > have any benefits. > > Signed-off-by: Heesub Shin Looks good to me, although I'm thinking to make it more aggressive. eg. minus two or three times of CHUNK_SIZE. > --- > mm/zbud.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/zbud.c b/mm/zbud.c > index 9bb4710..ad1e781 100644 > --- a/mm/zbud.c > +++ b/mm/zbud.c > @@ -257,7 +257,7 @@ int zbud_alloc(struct zbud_pool *pool, int size, gfp_t gfp, > > if (size <= 0 || gfp & __GFP_HIGHMEM) > return -EINVAL; > - if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED) > + if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) > return -ENOSPC; > chunks = size_to_chunks(size); > spin_lock(&pool->lock); > -- Regards, -Bob -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org